2-2_Flow_control_Lists.ipynb

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    "# Lecture 2-2\n",
    "\n",
    "# Flow Control; Lists\n",
    "\n",
    "## Week 2 Wednesday\n",
    "\n",
    "## Miles Chen, PhD\n",
    "\n",
    "### Adapted from *Think Python* by Allen B. Downey and *A Whirlwind Tour of Python* by Jake VanderPlas"
   ]
  },
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   "cell_type": "markdown",
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   "source": [
    "# if-elif-else\n",
    "\n",
    "The basic statement for control the flow of execution are the if-elif-else conditional statements.\n",
    "\n",
    "- There is no need to use parenthesis in the conditional statements.\n",
    "- Use a colon to end the conditional statement.\n",
    "- Lines indented after the colon are associated with the if statement.\n",
    "- When there is no longer indentation, the lines are no longer associated with the if statement.\n",
    "- `elif` (else if) and `else` must be on the same level of indentation as the first `if` statement."
   ]
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    {
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     "output_type": "stream",
     "text": [
      "-3 must be negative\n"
     ]
    }
   ],
   "source": [
    "x = -3\n",
    "\n",
    "if x == 0:\n",
    "    print(x, 'is zero')\n",
    "elif x > 0:\n",
    "    print(x, 'is positive')\n",
    "else:\n",
    "    print(x, 'must be negative')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
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    "tags": []
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   "source": [
    "Like other languages, the `elif` or `else` statements are only executed if the original `if` statement is false"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "100 is positive\n"
     ]
    }
   ],
   "source": [
    "x = 100\n",
    "\n",
    "if x > 0:\n",
    "    print(x, 'is positive')\n",
    "elif x > 3:\n",
    "    print(x, 'is greater than 3')  # will not get executed\n",
    "else:\n",
    "    print(x, 'is zero or negative')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "## Nested Conditionals\n",
    "You can nest conditionals, but they can be hard to read and should be avoided when possible."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
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     "slide_type": "fragment"
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   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "x is a positive single-digit number.\n"
     ]
    }
   ],
   "source": [
    "x = 5\n",
    "if 0 < x:\n",
    "    if x < 10:\n",
    "        print('x is a positive single-digit number.')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
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   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "x is a positive single-digit number.\n"
     ]
    }
   ],
   "source": [
    "# better alternative\n",
    "if 0 < x and x < 10:\n",
    "    print('x is a positive single-digit number.')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
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   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "x is a positive single-digit number.\n"
     ]
    }
   ],
   "source": [
    "# concise format:\n",
    "if 0 < x < 10:\n",
    "    print('x is a positive single-digit number.')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "# Recursion\n",
    "\n",
    "When you write a recursive function, the function calls itself inside the function.\n",
    "\n",
    "When you write a recursive function, there should always be a base case that does not call the function recursively. This will end the function to avoid it from running forever."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {
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   "outputs": [],
   "source": [
    "def countdown(n):\n",
    "    if n <= 0:\n",
    "        print('Blastoff!')\n",
    "    else:\n",
    "        print(n)\n",
    "        countdown(n - 1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {
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   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "3\n",
      "2\n",
      "1\n",
      "Blastoff!\n"
     ]
    }
   ],
   "source": [
    "countdown(3)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
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   },
   "source": [
    "+ The execution of countdown begins with n=3, and since n is greater than 0, it prints the value 3, and then calls itself with n=2\n",
    "    + The execution of countdown begins with n=2, and since n is greater than 0, it prints the value 2, and then calls itself with n = 1\n",
    "        - The execution of countdown begins with n=1, and since n is greater than 0, it prints the value 1, and then calls itself with n = 0\n",
    "             - The execution of countdown begins with n=0, and since n is not greater than 0, it prints the word, “Blastoff!” and then returns.\n",
    "        - The countdown that got n=1 returns.\n",
    "    - The countdown that got n=2 returns.\n",
    "+ The countdown that got n=3 returns."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
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   },
   "outputs": [],
   "source": [
    "# another example\n",
    "# a function that prints a string n times"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
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   },
   "outputs": [],
   "source": [
    "def print_n(s, n):\n",
    "    if n <= 0:\n",
    "        return None # exits the function\n",
    "    print(s)\n",
    "    print_n(s, n - 1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "hello\n",
      "hello\n",
      "hello\n"
     ]
    }
   ],
   "source": [
    "print_n(\"hello\", 3)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "Factorial function is also a good candidate for recursion.\n",
    "\n",
    "- 4! = 4 * 3!\n",
    "- 3! = 3 * 2!\n",
    "- 2! = 2 * 1!\n",
    "- 1! = 1 * 0!\n",
    "- 0! = 1"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
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   },
   "outputs": [],
   "source": [
    "def factorial(n):\n",
    "    if n <= 0:\n",
    "        return 1\n",
    "    else:\n",
    "        return n * factorial(n - 1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "24"
      ]
     },
     "execution_count": 12,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "factorial(4)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "120"
      ]
     },
     "execution_count": 13,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "factorial(5)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    },
    "tags": []
   },
   "source": [
    "# for loops\n",
    "\n",
    "It is technically possible to accomplish all forms of repetition with recursion only. However, repetition can also be achieved using other coding forms like loops.\n",
    "\n",
    "The most basic loop type is the for loop, which will repeat the associated lines of code for each value in an iterable. Python has several iterable data structures (list, tuple, range, strings, etc.) which will be covered in more detail later."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {
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     "slide_type": "fragment"
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    "tags": []
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "5\n",
      "running sum is: 5\n",
      "7\n",
      "running sum is: 12\n",
      "2\n",
      "running sum is: 14\n",
      "1\n",
      "running sum is: 15\n"
     ]
    }
   ],
   "source": [
    "values = [5, 7, 2, 1]\n",
    "y = 0\n",
    "for x in values:\n",
    "    print(x)\n",
    "    y += x  # short for y = y + x\n",
    "    print('running sum is:', y)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    },
    "tags": []
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "U!\n",
      "C!\n",
      "L!\n",
      "A!\n",
      " !\n",
      "U!\n",
      "C!\n",
      "L!\n",
      "A!\n"
     ]
    }
   ],
   "source": [
    "for a in \"ucla ucla\":\n",
    "    print(a.upper() + \"!\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    },
    "tags": []
   },
   "source": [
    "## The range object"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "If you want just a sequence of numbers, you can use a `range()` object.\n",
    "\n",
    "`range(10)` is similar to writing 0:9 in R. It creates a range of indexes that is 10 items long and begins with index 0.\n",
    "\n",
    "The general format is \n",
    "\n",
    "`range( start , end , step size)`\n",
    "\n",
    "by default, the range will begin at the start value, increment by step size, and go up to but not include the end value. If you only specify one integer value, it will assume start = 0 and step size is 1."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": []
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "range(0, 10)"
      ]
     },
     "execution_count": 16,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "range(10)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": []
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0 1 2 3 4 5 6 7 8 9 "
     ]
    }
   ],
   "source": [
    "for i in range(10):\n",
    "    print(i, end = ' ') \n",
    "    # the end argument tells python to use a space rather than a new line"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 18,
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    },
    "tags": []
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "range(5, 10)"
      ]
     },
     "execution_count": 18,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "range(5,10)  # creates a range from 5 up to but not including 10"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": []
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[5, 6, 7, 8, 9]"
      ]
     },
     "execution_count": 19,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "list(range(5,10))  # if you want to see the actual values, throw in list"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": []
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[0, 2, 4, 6, 8, 10, 12, 14, 16, 18]"
      ]
     },
     "execution_count": 20,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "list(range(0, 20, 2))  # range from 0 to 20 by 2"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": []
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20]"
      ]
     },
     "execution_count": 21,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "list(range(0, 21, 2))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 22,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": [
     "raises-exception"
    ]
   },
   "outputs": [
    {
     "ename": "TypeError",
     "evalue": "'float' object cannot be interpreted as an integer",
     "output_type": "error",
     "traceback": [
      "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[1;31mTypeError\u001b[0m                                 Traceback (most recent call last)",
      "\u001b[1;32m~\\AppData\\Local\\Temp\\ipykernel_31444\\4186440163.py\u001b[0m in \u001b[0;36m<module>\u001b[1;34m\u001b[0m\n\u001b[1;32m----> 1\u001b[1;33m \u001b[0mlist\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mrange\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;36m0\u001b[0m\u001b[1;33m,\u001b[0m \u001b[1;36m20.1\u001b[0m\u001b[1;33m,\u001b[0m \u001b[1;36m2\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m)\u001b[0m  \u001b[1;31m#does not accept floats as arguments\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m",
      "\u001b[1;31mTypeError\u001b[0m: 'float' object cannot be interpreted as an integer"
     ]
    }
   ],
   "source": [
    "list(range(0, 20.1, 2))  #does not accept floats as arguments"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 23,
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    },
    "tags": []
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[10, 9, 8, 7, 6]"
      ]
     },
     "execution_count": 23,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "list(range(10,5,-1)) # need to specify a negative step"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 24,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": []
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[]"
      ]
     },
     "execution_count": 24,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "list(range(10,5)) # otherwise you get no values in your list"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    },
    "tags": []
   },
   "source": [
    "# while loops\n",
    "\n",
    "Another common loop is the while loop. It repeats the associated code until the conditional statement is False"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 25,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": []
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0 1 2 3 4 5 6 7 8 9 "
     ]
    }
   ],
   "source": [
    "i = 0\n",
    "while i < 10:\n",
    "    print(i, end=' ')\n",
    "    i += 1"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 26,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": []
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "10"
      ]
     },
     "execution_count": 26,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "i"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    },
    "tags": []
   },
   "source": [
    "## break and continue\n",
    "\n",
    "- The break statement breaks-out of the loop entirely\n",
    "- The continue statement skips the remainder of the current loop, and goes to the next iteration"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 27,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": []
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "1 3 5 7 9 11 13 15 17 19 "
     ]
    }
   ],
   "source": [
    "for n in range(20):\n",
    "    # if the remainder of n / 2 is 0, skip the rest of the loop\n",
    "    if n % 2 == 0:\n",
    "        continue\n",
    "    print(n, end=' ')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "an example to create fibonacci numbers"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 28,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": []
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89]\n"
     ]
    }
   ],
   "source": [
    "a, b = 0, 1   # you can assign multiple values using tuples\n",
    "amax = 100    # set a maximum value\n",
    "L = []\n",
    "\n",
    "while True:    # the while True will run forever until it reaches a break\n",
    "    (a, b) = (b, a + b)\n",
    "    if a > amax:\n",
    "        break\n",
    "    L.append(a)\n",
    "\n",
    "print(L)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "# Boolean expressions\n",
    "\n",
    "All conditional statements rely on the use of boolean expressions."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 29,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 29,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "5 == 5"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 30,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "False"
      ]
     },
     "execution_count": 30,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "5 == 6"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 31,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 31,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "5 != 6"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 32,
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "False"
      ]
     },
     "execution_count": 32,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "5 > 6"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 33,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 33,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "5 < 6"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 34,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "False"
      ]
     },
     "execution_count": 34,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "5 >= 6"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 35,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 35,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "5 <= 6"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 36,
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    },
    "tags": []
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "False"
      ]
     },
     "execution_count": 36,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "\"5\" == 5"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "When comparing strings, greater than or less than is determined by alphabetical order, with things coming earlier in the alphabet being \"less than\" things later in the alphabet.\n",
    "\n",
    "All upper case letters come before all lower case letters"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 37,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": []
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 37,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "\"A\" < \"B\""
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 38,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": []
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 38,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "\"A\" <\"a\""
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 39,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": []
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 39,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "\"Z\" < \"a\""
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 40,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": []
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 40,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "\"a\" < \"z\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "## Logical operators\n",
    "\n",
    "`and` `or` `not` are written in lowercase"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 41,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 41,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "True and True"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 42,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "False"
      ]
     },
     "execution_count": 42,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "True and False"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 43,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 43,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "True or False"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 44,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "False"
      ]
     },
     "execution_count": 44,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "not True"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 45,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 45,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "not False"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 46,
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 46,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "False or not False"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 47,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 47,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "True and not False"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "The idiom `x % y == 0` is a way to check if x is divisible by y."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 48,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 48,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "n = 6\n",
    "n % 2 == 0 and n % 3 == 0"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 49,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "False"
      ]
     },
     "execution_count": 49,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "n = 8\n",
    "n % 2 == 0 and n % 3 == 0"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 50,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "True"
      ]
     },
     "execution_count": 50,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "n = 8\n",
    "n % 2 == 0 or n % 3 == 0"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    },
    "tags": []
   },
   "source": [
    "# A little bit on strategies for writing functions\n",
    "\n",
    "When writing a function, I advise against going straight to writing the function. \n",
    "\n",
    "You should first write code in the global environment to achieve the desired task.\n",
    "\n",
    "Once you achieve this, then you can encapsulate the lines within a function."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "```\n",
    "# pseudo code for drawing a square\n",
    "\n",
    "go_forward(100) # value in px\n",
    "turn_left(90) # value in degrees\n",
    "go_forward(100)\n",
    "turn_left(90)\n",
    "go_forward(100)\n",
    "turn_left(90)\n",
    "go_forward(100)\n",
    "turn_left(90)\n",
    "\n",
    "```"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    },
    "tags": []
   },
   "source": [
    "# Encapsulation\n",
    "\n",
    "At the most basic level, a function encapsulates a few lines of code. This associates a name with statements and allows us to reuse the code.\n",
    "\n",
    "For example let's say we wanted to write some functions for drawing shapes:"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": []
   },
   "source": [
    "```\n",
    "# psuedo code\n",
    "def draw_square():\n",
    "    for i in range(4):\n",
    "        go_forward(100) # value in px\n",
    "        turn_left(90) # value in degrees\n",
    "```"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    },
    "tags": []
   },
   "source": [
    "# Generalization\n",
    "\n",
    "Generalization adds variables to functions so that the same function can be slightly altered."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "```\n",
    "# further generalize by adding an argument for length\n",
    "def draw_square(length):\n",
    "    for i in range(4):\n",
    "        go_forward(length)\n",
    "        turn_left(90)\n",
    "```"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    },
    "tags": []
   },
   "source": [
    "## more generalization of the function:\n",
    "\n",
    "We can make a polygon function."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": []
   },
   "source": [
    "Draw a pentagon\n",
    "```\n",
    "angle = 360 / 5\n",
    "for i in range(5):\n",
    "    go_forward(100)\n",
    "    turn_left(angle)\n",
    "```"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": []
   },
   "source": [
    "Draw a hexagon\n",
    "```\n",
    "angle = 360 / 6\n",
    "for i in range(6):\n",
    "    go_forward(100)\n",
    "    turn_left(angle)\n",
    "```"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": []
   },
   "source": [
    "After creating the code for a pentagon and hexagon, we can generalize to an n sided polygon:\n",
    "```\n",
    "def polygon(t, n, length):\n",
    "    angle = 360 / n\n",
    "    for i in range(n):\n",
    "        go_forward(length)\n",
    "        turn_left(angle)\n",
    "```"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "# Lists\n",
    "\n",
    "We will start with lists in Python"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "source": [
    "## List Creation\n",
    "Use square brackets. Lists can contain any mix of data types. You can nest lists inside other lists."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 51,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "fam = [\"liz\", 1.73, \"emma\", 1.68, \"mom\", 1.71, \"dad\", 1.89]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 52,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "fam2 = [[\"liz\", 1.73],\n",
    "[\"emma\", 1.68],\n",
    "[\"mom\", 1.71],\n",
    "[\"dad\", 1.89]]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 53,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['liz', 1.73, 'emma', 1.68, 'mom', 1.71, 'dad', 1.89]"
      ]
     },
     "execution_count": 53,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "fam"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 54,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[['liz', 1.73], ['emma', 1.68], ['mom', 1.71], ['dad', 1.89]]"
      ]
     },
     "execution_count": 54,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "fam2"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "## Subsetting lists\n",
    "- index starts at 0 (hardest part to adapt for R users)\n",
    "- use a series of square brackets for nested lists\n",
    "- use negative numbers to count from the end"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 55,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'liz'"
      ]
     },
     "execution_count": 55,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "fam[0]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 56,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['liz', 1.73]"
      ]
     },
     "execution_count": 56,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "fam2[0]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 57,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "'liz'"
      ]
     },
     "execution_count": 57,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "fam2[0][0]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 58,
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "1.89"
      ]
     },
     "execution_count": 58,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "fam[-1]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 59,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['dad', 1.89]"
      ]
     },
     "execution_count": 59,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "fam2[-1]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 60,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "1.89"
      ]
     },
     "execution_count": 60,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "fam2[-1][-1]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "## List Slicing\n",
    "Note that the slice will not include the item in the index after the colon.\n",
    "You can think of the 'slice' happening at the commas corresponding to the number.\n",
    "So fam[1:3] slices the list at the first and third commas, and extracts [1.73, 'emma']"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 61,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[1.73, 'emma']"
      ]
     },
     "execution_count": 61,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "fam = [\"liz\", 1.73, \"emma\", 1.68, \"mom\", 1.71, \"dad\", 1.89]\n",
    "fam[1:3]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 62,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[1.73]"
      ]
     },
     "execution_count": 62,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "fam[1:2]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 63,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "1.73"
      ]
     },
     "execution_count": 63,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "fam[1]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 64,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[]"
      ]
     },
     "execution_count": 64,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "fam[1:1]  # there is nothing between the first and first commas"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 65,
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['liz', 1.73]"
      ]
     },
     "execution_count": 65,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "fam[0:2]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 66,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['dad', 1.89]"
      ]
     },
     "execution_count": 66,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "fam[6:8]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 67,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['emma', 1.68, 'mom', 1.71, 'dad', 1.89]"
      ]
     },
     "execution_count": 67,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "fam[2:]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 68,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['liz', 1.73, 'emma', 1.68]"
      ]
     },
     "execution_count": 68,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "fam[:4]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 69,
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['liz', 1.73, 'emma', 1.68, 'mom', 1.71, 'dad', 1.89]"
      ]
     },
     "execution_count": 69,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "fam[:]  # slice with no indices will create a (shallow) copy of the list."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 70,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": [
     "raises-exception"
    ]
   },
   "outputs": [
    {
     "ename": "SyntaxError",
     "evalue": "invalid syntax (488845688.py, line 1)",
     "output_type": "error",
     "traceback": [
      "\u001b[1;36m  File \u001b[1;32m\"C:\\Users\\miles\\AppData\\Local\\Temp\\ipykernel_31444\\488845688.py\"\u001b[1;36m, line \u001b[1;32m1\u001b[0m\n\u001b[1;33m    fam[] # throws error\u001b[0m\n\u001b[1;37m        ^\u001b[0m\n\u001b[1;31mSyntaxError\u001b[0m\u001b[1;31m:\u001b[0m invalid syntax\n"
     ]
    }
   ],
   "source": [
    "fam[] # throws error"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 71,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['liz', 1.73, 'emma', 1.68, 'mom', 1.71, 'dad', 1.89]\n",
      "[1.68, 'mom', 1.71]\n"
     ]
    }
   ],
   "source": [
    "fam = [\"liz\", 1.73, \"emma\", 1.68, \"mom\", 1.71, \"dad\", 1.89]\n",
    "print(fam)\n",
    "print(fam[-5:-2])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 72,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[['liz', 1.73], ['emma', 1.68], ['mom', 1.71], ['dad', 1.89]]"
      ]
     },
     "execution_count": 72,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "fam2"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 73,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[['emma', 1.68], ['mom', 1.71]]"
      ]
     },
     "execution_count": 73,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "fam2[1:3]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 74,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['emma']"
      ]
     },
     "execution_count": 74,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "fam2[1:3][0][0:1]"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "## Lists are mutable\n",
    "This means that methods change the lists themselves. \n",
    "If the list is assigned to another name, both names refer to the exact same object."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 75,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['liz', 1.73, 'emma', 1.68, 'mom', 1.71, 'dad', 1.89]\n",
      "['sister', 1.73, 'emma', 1.68, 'mom', 1.71, 'dad', 1.89]\n",
      "['sister', 1.73, 'emma', 1.68, 'mom', 1.71, 'dad', 1.89]\n"
     ]
    }
   ],
   "source": [
    "fam = [\"liz\", 1.73, \"emma\", 1.68, \"mom\", 1.71, \"dad\", 1.89]\n",
    "print(fam)\n",
    "second = fam    # second references fam. second is not a copy of fam.\n",
    "second[0] = \"sister\"  # we make a change to the list 'second'\n",
    "print(second)\n",
    "print(fam) # changing the list 'second' has changed the list 'fam'"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 76,
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['liz', 1.73, 'emma', 1.68, 'mom', 1.71, 'dad', 1.89]\n",
      "['sister', 1.73, 'emma', 1.68, 'mom', 1.71, 'dad', 1.89]\n",
      "['liz', 1.73, 'emma', 1.68, 'mom', 1.71, 'dad', 1.89]\n"
     ]
    }
   ],
   "source": [
    "fam = [\"liz\", 1.73, \"emma\", 1.68, \"mom\", 1.71, \"dad\", 1.89]\n",
    "print(fam)\n",
    "second = fam[:]  # creates a copy of the list\n",
    "# second = fam.copy() # you can also create a list using the copy() method\n",
    "second[0] = \"sister\"\n",
    "print(second)\n",
    "print(fam) # changing the list second does not modify fam because second is a copy"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 77,
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['liz', 1.73, 'emma', 1.68, 'mom', 1.71, 'dad', 1.89]\n",
      "['liz', 1.65, 'emma', 1.68, 'mom', 1.71, 'dad', 1.89]\n",
      "['liz', 1.73, 'emma', 1.68, 'mom', 1.71, 'dad', 1.89]\n"
     ]
    }
   ],
   "source": [
    "third = fam.copy()\n",
    "print(third)\n",
    "third[1] = 1.65\n",
    "print(third)\n",
    "print(fam)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 78,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['liz', 1.73, 'emma', 1.68, 'mom', 1.71, 'dad', 1.89]"
      ]
     },
     "execution_count": 78,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "fam"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 79,
   "metadata": {},
   "outputs": [],
   "source": [
    "list2 = list(fam)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 80,
   "metadata": {},
   "outputs": [],
   "source": [
    "list2[1] = 1.9"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 81,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['liz', 1.9, 'emma', 1.68, 'mom', 1.71, 'dad', 1.89]"
      ]
     },
     "execution_count": 81,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "list2"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 82,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['liz', 1.73, 'emma', 1.68, 'mom', 1.71, 'dad', 1.89]"
      ]
     },
     "execution_count": 82,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "fam"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "You can use list slicing in conjuction with assignment to change values"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 83,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['liz', 1.73, 'emma', 1.68, 'mom', 1.71, 'dad', 1.89]\n",
      "['liz', 1.8, 'jenny', 1.68, 'mom', 1.71, 'dad', 1.89]\n"
     ]
    }
   ],
   "source": [
    "print(fam)\n",
    "fam[1:3] = [1.8, \"jenny\"]\n",
    "print(fam)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    },
    "tags": []
   },
   "source": [
    "# List Methods\n",
    "\n",
    "- `list.copy()`\n",
    "    - Return a shallow copy of the list. Equivalent to a[:]\n",
    "- `list.append(x)`\n",
    "    - Add an item to the end of the list. Equivalent to a[len(a):] = [x]."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 84,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": []
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['liz', 1.73, 'emma', 1.68, 'mom', 1.71, 'dad', 1.89, 'me']\n"
     ]
    }
   ],
   "source": [
    "fam = [\"liz\", 1.73, \"emma\", 1.68, \"mom\", 1.71, \"dad\", 1.89]\n",
    "fam.append(\"me\")   # unlike R, you don't have to \"capture\" the result of the function. \n",
    "# the list itself is modified. You can only append one item.\n",
    "print(fam)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 85,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['liz', 1.73, 'emma', 1.68, 'mom', 1.71, 'dad', 1.89, 'me', 1.8]\n"
     ]
    }
   ],
   "source": [
    "fam = fam + [1.8]  # you can also append to a list with the addition `+` operator\n",
    "# note that this output needs to be 'captured' and assigned back to fam\n",
    "print(fam)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 86,
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "outputs": [],
   "source": [
    "fam.append('miles')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 87,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": []
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['liz', 1.73, 'emma', 1.68, 'mom', 1.71, 'dad', 1.89, 'me', 1.8, 'miles']"
      ]
     },
     "execution_count": 87,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "fam"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 88,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": []
   },
   "outputs": [],
   "source": [
    "fam.append(['miles', 1.78, 'joe', 1.8]) # append will add the entire object as one list entry"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 89,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['liz',\n",
       " 1.73,\n",
       " 'emma',\n",
       " 1.68,\n",
       " 'mom',\n",
       " 1.71,\n",
       " 'dad',\n",
       " 1.89,\n",
       " 'me',\n",
       " 1.8,\n",
       " 'miles',\n",
       " ['miles', 1.78, 'joe', 1.8]]"
      ]
     },
     "execution_count": 89,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "fam"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 90,
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['liz',\n",
       " 1.73,\n",
       " 'emma',\n",
       " 1.68,\n",
       " 'mom',\n",
       " 1.71,\n",
       " 'dad',\n",
       " 1.89,\n",
       " 'miles',\n",
       " 1.78,\n",
       " 'joe',\n",
       " 1.8]"
      ]
     },
     "execution_count": 90,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "fam = [\"liz\", 1.73, \"emma\", 1.68, \"mom\", 1.71, \"dad\", 1.89]\n",
    "fam + ['miles', 1.78, 'joe', 1.8] # plus operator concatenates the lists"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 91,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['liz', 1.73, 'emma', 1.68, 'mom', 1.71, 'dad', 1.89]"
      ]
     },
     "execution_count": 91,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "fam"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    },
    "tags": []
   },
   "source": [
    "#### Copy vs. Deep Copy Example\n",
    "\n",
    "`list.copy` and `list[:]` both create shallow copies. A shallow copy creates a copy of the list, but does not create copies of any objects that the list references.\n",
    "\n",
    "a deep copy will copy the list and create copies of objects that the list references."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 92,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": []
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[['a', 1, 2], ['b', 3, 4], 'x']\n",
      "[['a', 1, 2], ['b', 3, 4]]\n",
      "[['a', 1, 2], ['b', 3, 4]]\n"
     ]
    }
   ],
   "source": [
    "a = [\"a\", 1, 2]\n",
    "b = [\"b\", 3, 4]\n",
    "c = [a, b]\n",
    "\n",
    "import copy\n",
    "d = c[:]  # d is a shallow copy of c\n",
    "e = copy.deepcopy(c)  # e is a deep copy of c\n",
    "\n",
    "c.append(\"x\")  # modify c\n",
    "print(c) # c reflects the change\n",
    "print(d) # d is a copy and is not changed\n",
    "print(e) # e is a copy and is not changed"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 93,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": []
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[['a', 1, 2, 'z'], ['b', 3, 4], 'x']\n",
      "[['a', 1, 2, 'z'], ['b', 3, 4]]\n",
      "[['a', 1, 2], ['b', 3, 4]]\n"
     ]
    }
   ],
   "source": [
    "a.append(\"z\")  # modify list a, an element in c\n",
    "print(c) # c reflects change\n",
    "print(d) # d copies the structure of c and reflects the change\n",
    "print(e) # is a deep copy and is not affected by changes to underlying elements"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "- `list.insert(i, x)`\n",
    "    - Insert an item at a given position. The first argument is the index of the element before which to insert, so a.insert(0, x) inserts at the front of the list, and a.insert(len(a), x) is equivalent to a.append(x).\n",
    "\n",
    "- `list.extend(iterable)`\n",
    "    - Extend the list by appending all the items from the iterable. Equivalent to a[len(a):] = iterable."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 94,
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['liz', 1.73, 'emma', 1.68, 'joe', 'mom', 1.71, 'dad', 1.89]\n"
     ]
    }
   ],
   "source": [
    "fam = [\"liz\", 1.73, \"emma\", 1.68, \"mom\", 1.71, \"dad\", 1.89]\n",
    "fam.insert(4, \"joe\") # inserts joe at the location of the 4th comma between 1.68 and mom\n",
    "print(fam)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 95,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": []
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['liz', 1.73, 'emma', 1.68, ['joe', 2.0], 'mom', 1.71, 'dad', 1.89]\n"
     ]
    }
   ],
   "source": [
    "fam = [\"liz\", 1.73, \"emma\", 1.68, \"mom\", 1.71, \"dad\", 1.89]\n",
    "fam.insert(4, [\"joe\", 2.0])  # trying to insert multiple items by using a list inserts a list\n",
    "print(fam)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 96,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": [
     "raises-exception"
    ]
   },
   "outputs": [
    {
     "ename": "TypeError",
     "evalue": "insert() takes exactly 2 arguments (3 given)",
     "output_type": "error",
     "traceback": [
      "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[1;31mTypeError\u001b[0m                                 Traceback (most recent call last)",
      "\u001b[1;32m~\\AppData\\Local\\Temp\\ipykernel_31444\\1622468637.py\u001b[0m in \u001b[0;36m<module>\u001b[1;34m\u001b[0m\n\u001b[0;32m      1\u001b[0m \u001b[0mfam\u001b[0m \u001b[1;33m=\u001b[0m \u001b[1;33m[\u001b[0m\u001b[1;34m\"liz\"\u001b[0m\u001b[1;33m,\u001b[0m \u001b[1;36m1.73\u001b[0m\u001b[1;33m,\u001b[0m \u001b[1;34m\"emma\"\u001b[0m\u001b[1;33m,\u001b[0m \u001b[1;36m1.68\u001b[0m\u001b[1;33m,\u001b[0m \u001b[1;34m\"mom\"\u001b[0m\u001b[1;33m,\u001b[0m \u001b[1;36m1.71\u001b[0m\u001b[1;33m,\u001b[0m \u001b[1;34m\"dad\"\u001b[0m\u001b[1;33m,\u001b[0m \u001b[1;36m1.89\u001b[0m\u001b[1;33m]\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m----> 2\u001b[1;33m \u001b[0mfam\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0minsert\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;36m4\u001b[0m\u001b[1;33m,\u001b[0m \u001b[1;34m\"joe\"\u001b[0m\u001b[1;33m,\u001b[0m \u001b[1;36m2.0\u001b[0m\u001b[1;33m)\u001b[0m  \u001b[1;31m# like append, you can only insert one item\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m\u001b[0;32m      3\u001b[0m \u001b[1;31m# trying to insert multiple items causes and error\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m      4\u001b[0m \u001b[0mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mfam\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n",
      "\u001b[1;31mTypeError\u001b[0m: insert() takes exactly 2 arguments (3 given)"
     ]
    }
   ],
   "source": [
    "fam = [\"liz\", 1.73, \"emma\", 1.68, \"mom\", 1.71, \"dad\", 1.89]\n",
    "fam.insert(4, \"joe\", 2.0)  # like append, you can only insert one item\n",
    "# trying to insert multiple items causes and error\n",
    "print(fam)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 97,
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['liz', 1.73, 'emma', 1.68, 'mom', 1.71, 'dad', 1.89, 'joe', 2.0]\n"
     ]
    }
   ],
   "source": [
    "fam = [\"liz\", 1.73, \"emma\", 1.68, \"mom\", 1.71, \"dad\", 1.89]\n",
    "fam.extend([\"joe\", 2.0]) # lets you add multiple items, but at the end\n",
    "print(fam)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 98,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    },
    "tags": []
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['liz', 1.73, 'emma', 1.68, 'joe', 2.0, 'mom', 1.71, 'dad', 1.89]\n"
     ]
    }
   ],
   "source": [
    "fam = [\"liz\", 1.73, \"emma\", 1.68, \"mom\", 1.71, \"dad\", 1.89]\n",
    "fam[4:4] = [\"joe\", 2.0] # Use slice and assignment to insert multiple items in a specific position\n",
    "print(fam)"
   ]
  }
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